The present invention relates to a novel multi-core conductive wire to be used for various sorts of electric equipment, and more particularly to a multi-core conductive wire having a novel terminal and its manufacturing method.
In the prior art, various methods have been used as a processing method of a terminal portion of a multi-core conductive wire (called conductive wire and multi-core wire) to be used in electric equipment. As called a multi-core conductive wire, since a large number of wires are used in the conductive wire, a simple method of processing a terminal portion in such a multi-core conductive wire has not been yet established, being in difficulties.
On the other hand, in the processing of the terminal portion of the multi-core conductive wire, also such technology is demanded that other material wrapping the multi-core conductive wire is not used but the processing can be performed by only the multi-core conductive wire.
As a method of processing a terminal portion in the prior art, when a relatively small number of multi-core conductive wires are used, the conductive wires are fixedly secured to each other using a resistance welder. When a large number of multi-core conductive wires are used, the fixing by the resistance welder is restricted. Therefore as a fixing method in the present state, plating is applied to the individual multi-core conductive wires and the terminal portion is fixedly secured by the resistance welder utilizing the plating.
Respective methods have some merits and demerits. For example, with the former, if the wires are welded with each other, the wires are heated up to the processing temperature which may attain to the melting point thereof. Therefore the thermal damage of the wires themselves becomes great, resulting in increase of the resistance being fatal as the electric equipment. Also with the latter, since the plating is applied to the individual wires, the price of the wires themselves becomes expensive. Further flexibility required as other factor is deteriorated due to the plating film and the fixing by the resistance welding.
As above described, any method of processing a terminal portion in the prior art has some disadvantages. As a result, it is difficult to process a terminal portion of a multi-core conductive wire with high quality.
In order to connect a terminal portion to other connection terminal, such a method is generally performed that a conductive wire is inserted in a connecting conductor terminal, and the terminal having lateral spread and the conductive wire are joined with each other by means of soft soldering or caulking. That is, a conductive wire peeled off an insulation tube is inserted into a connecting conductor terminal and is soldered by means of soft soldering. Otherwise, a conductor wire peeled off an insulation tube is inserted into a connecting conductor terminal and is pressure-contacted for connection by a caulking machine. The above-mentioned connection in the processing of the terminal portion of the multi-core conductive wire is performed by other material for wrapping the multi-core conductive wire.
Japanese Patent Laid-open No. Hei 1-292775 discloses a method that an end portion of a multi-core conductive wire is previously inserted in a metal cylinder, and the metal cylinder is processed and molded into a terminal. Also Japanese Patent Laid-open No. Sho 55-113279 discloses that an end portion of a multi-core conductive wire is bundled by a wire, and then is subjected to pressuremolding into a flat end portion and is brazed with other conductor by resistance heating.
In rotary machines such as a motor or an AC generator, or electric equipment for electric facilities of an automobile, for a breaker or the like, in order to exhibit functions respectively, multi-core conductive wires are used widely as conductive wires. Processing of a terminal portion plays a very important role. Two methods are used in processing of a terminal portion. One is the case that a terminal portion of a conductive wire is connected to other connection terminal as above described, and the other is the case that a terminal portion of a conductive wire is fixedly secured and is treated as a single article. Even in a single article of the latter, it may sometimes be coupled with other conductor terminal. The multi-core conductive wires are used in various sorts of electric equipment. Attendant on this, various sorts of conductor wires are applied. That is, there are conductive wires being different from each other in the diameter of wire, the number of wires or the like. Therefore it is desirable that processing of terminal portions of these conductive wires be easily performed.
When the number of the conductive wires in the terminal portion is in the range of three to a large number (for example, 10,000), and moreover a range of the wire diameter is, for example, from 0.10 mm to 1.5 mm, approximately, it is very difficult that all different conductive wires are fixedly secured together in the method of the prior art. Thus such structure for a terminal portion with high reliability has been desired strongly that terminal portions of many conductive wires having wire diameters ranging from smaller one to larger one can be fixedly secured without raising the heating temperature in the terminal portions if possible and without applying the plating or the like to the wires if possible.
The methods disclosed in Japanese Patent Laid-open No. Hei 1-292775 and Japanese Patent Laid-open No. Sho 55-11327 have problems in that the coupling force between the wires is weak and further the number of the manufacturing processes is much.
An object of the present invention is to provide a multi-core conductive wire having the small number of manufacturing processes, a terminal with high strength, and a method of manufacturing the multi-core conductive wire.
The present invention provides a multi-core conductive wire wherein in such irregular and uneven state that a molded end portion of a multi-core conductive wire or individual strands of the multi-core conductive wire are partially entangled with each other in disorder, the multi-core conductive wire is subjected to compression-molding, pressure-molding or plastic working.
The present invention provides a multi-core conductive wire wherein in such irregular and uneven state that a molded end portion of a multi-core conductive wire or individual strands of the multi-core conductive wire are partially entangled with each other in disorder, the multi-core conductive wire is subjected to processing or molding in similar manner to that as above described, and a hole or the like to enable connection to other connection terminal is processed.
The present invention provides a multi-core conductive wire wherein in such irregular and uneven state that a molded end portion of the multi-core conductive wire is entangled or the multi-core conductive wire is entangled with a molding assisting material in disorder, the multi-core conductive wire is subjected to processing or molding, and a hole or the like to enable connection to other terminal is processed.
As a molding assisting material as above described, preferably a material is selected from the group of consisting of copper, tin, lead, silver and indium and molded in linear shape, powder state, band shape, plating, thermal spraying or the like.
For a multi-core conductive wire which has a wire diameter ranging from 0.01 mm to 1.5 mm and the number of wire not less than 30 preferably not less than 100, the wire material of Cu, Al, Ag, Au or the like, may be used.
In the molded terminal structure of the present invention, it is preferable that the conductor wires being different in the wire diameter be combined, and that different wire materials be combined.
The present invention is characterized in that the multi-core conductive wire with the terminal portion subjected to molding as above described is connected to other conductor terminal.
The present invention provides a method of manufacturing a multi-core conductive wire, comprising: a processing step of molding an end portion of the multi-core conductive wire into irregular and uneven state where the end portion of the multi-core conductive wire or individual strands of the multi-core conductive wire are partially entangled with each other; a processing step of temporarily molding said molded end portion; and a step of applying compression- or plastic-working to said processed end portion and processing it into the molded article.
In the present invention, in order that the multi-core conductive wire has the electric performance, in view of the necessity for the terminal portion to be integrated at first, it is preferable that molding to desired shape be performed in cold processing without thermal damage, and that the terminal portion molded in cold processing be connected substantially to other electric conductor terminal.
The terminal portion molding can be achieved in that one end of the multi-core conductive wire is untied and the strands are entangled with each other in disorder, in irregular and uneven state for molding. The thus molded terminal portion can be sufficiently connected to other conductor terminal. The molded article can be provided with a hole or the like during the molding, and can be screwed utilizing the hole and also can be joined using a general brazing.
That is, the multi-core conductive wire of the present invention is constituted by stranded wire of copper. In this case, the multi-core conductive wire is constituted by six bundles of the stranded wires. The end portion is molded in such irregular and uneven state that the multi-core conductive wires are entangled with each other, and is integrally molded.
In some case, the end portion is connected to other conductor terminal. As an example of the joining method, resistance brazing using a resistance welder is preferable. The resistance welder is used here. Because the heating and the pressure applying can be performed simultaneously, and the joining can be performed in a short time. Since the joining is performed in the atmosphere in almost case, the shorter the joining time, the less the reaction with oxygen. Thus the good joint can be obtained. In order to make the junction more reliable, it is preferable that the resistance welder adopt the heating and pressure applying system in two stages.
In the case of the multi-core conductive wire, in the heating and the pressure applying at the first stage, the solder material with high resistance value is heated, and at the same time of the heating of the solder material, also the multi-core conductive wire is heated to certain temperature, and in the heating and pressure applying at the second stage, the material is melted and wets the wires of the multi-core conductive wire. Even if the solder material before the wires of the multi-core conductive wire are heated at a time, it is not liable to wet. Consequently the heating in the two stages is more preferable. The heating and pressure applying system in the two stages is a system to be used in the case where the multi-core conductive wires are relatively much. When the multi-core conductive wires are relatively a little, the heating and pressure applying system in one stage can perform the joining well.
As a solder material to be used in the present invention, a solder material containing phosphorous is preferable. As a solder material containing phosphorous, a solder material constituted by Cu alloy containing P 3 to 8%, further Ag 4 to 7% or 13 to 17% by weight, is preferable. Further such solder material may contain Sn and Au of 5% or less. In the solder material, during the joining, phosphorous removes oxide from the material to be joined and the wettability of the solder is improved and flux becomes unnecessary although it is usually required in the solder material. Thus the washing after the joining need not be performed, and the corrosion of the material to be joined due to the remaining of the flux used conventionally can be eliminated. Since the solder material containing phosphorous is preferably used in the resistance brazing, the solder foil is preferably arranged in the joining interface. Its thickness and width are determined by size of the molding structure.
When a hole is provided on the end portion of the multi-core conductive wire, the end portion can be connected mechanically to other conductor. The hole is produced by processing at the same time during the cold molding.
As a multi-core conductive wire material to perform the molding in the present invention, bare copper wire is used at almost case. In order that the compression force during the molding is decreased and the fixing force of the molded portion is made stronger, use of the molding assisting material is effective. Although various substance may be considered as the joining assisting material, selection of material softer than the multi-core conductive wire itself is preferable. Because when the molding is performed using the die, the soft material is elongated by the pressure application and is entangled with the wires of the multi-core conductive wire and has effect of improving the adhesibility of the multi-core conductive wire. As the material, soft copper, tin, lead, silver, indium or the like is recommended. The form in linear shape, powder state, band shape, plating, thermal spraying or the like is recommended.
In the state of molding the multi-core conductive wire, straight wire, stranded wire, net wire and the like are applied, and the size and the wire diameter of the multi-core conductive wire are varied in response to the conduction current in the electric performance.
Condition required in the multi-core conductive wire is the processing of the terminal portion of the multi-core conductive wire, in other words, that the conductive wires are electrically conducted with each other without fail, and that malfunction is not produced for use in a long period of time. In order to satisfy such condition, individual strands of the multi-core conductive wire are entangled with each other and the adhesibility between the strands is molded well.
As above described, the molded terminal structure portion of the multi-core conductive wire by the cold pressure-molding is molded in such irregular and uneven state that the strands are entangled with each other in disorder. Thus high fixing force and high binding force are exhibited between the individual strands and the molded terminal structure portion has high strength.
Also when the compressed terminal molded article is connected to other conductor terminal, for example, in the connection by brazing, the solder material wets both terminals and thereby good joining can be achieved. Also in the connection by screw or rivet system, electrically stable characteristics can be obtained.
In the molded terminal structure portion manufactured in such a manner, it is proved that the fixing force of the molded terminal structure portion itself is high. Also in the connection to other terminal portion, the satisfactory state can be obtained. That is, the molded terminal structure portion with little thermal damage can be obtained, and the multi-core conductive wire with high reliability can be confirmed.
In the multi-core conductive wire, various materials, such as electric copper wire, or silver wire, gold wire or respective wire materials subjected to, for example, tin plating called in JIS, can be applied as multi-core conductive wire of the present invention. As the terminal portion, also in shape such as square wire or elliptical wire, the manufacturing can be performed by the cold pressure-molding structure of the present invention.
In the multi-core conductive wires applied in the present invention, since bare wires are much used, the measure taking anticorrosive property and acid resisting property into consideration is effective. For example, it is confirmed that covering a lead wire and a terminal portion with an insulator contributes to improvement of reliability.
In rotary machines such as a motor or an AC generator, or electric equipment for electric facilities of an automobile, for a breaker and the like, in order to exhibit respective functions, multi-core conductive wires are used much and the present invention is used for these applications.